Qt中QAbstractTableModel、QItemDelegate的联合使用

1、继承QAbstractTableModel实现CurrencyModel,需要重写的函数有

introwCount(constQModelIndex&parent)const; //返回表的行数

intcolumnCount(constQModelIndex&parent)const;//返回表的列数

QVariantheaderData(intsection,Qt::Orientationorientation,introle)const;//用来显示表头信息

QVariantdata(constQModelIndex&index,introle)const;//用来显示表中的数据

Qt::ItemFlagsflags(constQModelIndex&index)const;//设置表项是否可编辑

boolsetData(constQModelIndex&index,constQVariant&value,introle=Qt::EditRole);//用来设置表的数据（指的是后台数据）

CurrencyModel.h头文件代码

#ifndef CURRENCYMODEL_H#define CURRENCYMODEL_H#include <QAbstractTableModel>#include <QMap>class CurrencyModel : public QAbstractTableModel{public:    CurrencyModel(QObject *parent = 0);    ~CurrencyModel();    void setCurrencyMap(const QMap<QString, double> &map);    bool insertRows(int row, int count, const QModelIndex &parent);    bool removeRows(int row, int count, const QModelIndex &parent);    int rowCount(const QModelIndex &parent) const;protected:    int columnCount(const QModelIndex &parent) const;    QVariant data(const QModelIndex &index, int role) const;    QVariant headerData(int section, Qt::Orientation orientation, int role) const;    bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole);    Qt::ItemFlags flags(const QModelIndex &index) const;public:    QMap<QString, double> currencyMap;private:    QString currencyAt(int offset) const;};#endif // CURRENCYMODEL_HCurrencyModel.cpp代码

#include "currencymodel.h"#include <QtDebug>CurrencyModel::CurrencyModel(QObject *parent):QAbstractTableModel(parent){}CurrencyModel::~CurrencyModel(){}void CurrencyModel::setCurrencyMap(const QMap<QString, double> &map){    beginResetModel();    currencyMap = map;    endResetModel();}int CurrencyModel::rowCount(const QModelIndex &parent) const{    return currencyMap.count();}int CurrencyModel::columnCount(const QModelIndex &parent) const{    return currencyMap.count();}QVariant CurrencyModel::data(const QModelIndex &index, int role) const{    if (!index.isValid()) return QVariant();    if (role == Qt::TextAlignmentRole) {        return int(Qt::AlignRight | Qt::AlignVCenter);    } else if (role == Qt::DisplayRole) {        QString rowCurrency = currencyAt(index.row());        QString columnCurrency = currencyAt(index.column());        if (index.column() == 1) return (currencyMap.begin() + index.row()).value(); //第二列表用来显示QComboBox选择的内容        if (currencyMap.value(rowCurrency) == 0.0) return "####";        double amount = currencyMap.value(columnCurrency) / currencyMap.value(rowCurrency);        return QString("%1").arg(amount, 0, 'f', 4);    }    return QVariant();}QVariant CurrencyModel::headerData(int section, Qt::Orientation orientation, int role) const{    if (role != Qt::DisplayRole) return QVariant();    return currencyAt(section);}QString CurrencyModel::currencyAt(int offset) const{    return (currencyMap.begin() + offset).key();}bool CurrencyModel::setData(const QModelIndex &index, const QVariant &value, int role){    if (role == Qt::EditRole) {        int row = index.row();        int  col = index.column();        currencyMap[(currencyMap.begin() + row).key()] = value.toDouble();        return true;    }    return false;}Qt::ItemFlags CurrencyModel::flags(const QModelIndex &index) const{    return Qt::ItemIsEditable | QAbstractTableModel::flags(index);}bool CurrencyModel::insertRows(int row, int count, const QModelIndex &parent){    beginInsertRows(QModelIndex(), row, row + count - 1);    endInsertRows();    return true;} bool CurrencyModel::removeRows(int row, int count, const QModelIndex &parent) {    beginRemoveRows(QModelIndex(), row, row + count - 1);    endRemoveRows();    return true; }

2、继承QItemDelegate实现itemDelegate类，要重载三个函数

<span style="color: rgb(128, 0, 128);">QWidget</span><span style="color: rgb(0, 0, 0);">*</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(0, 0, 0); font-style: italic;">createEditor</span><span style="color: rgb(0, 0, 0);">(</span><span style="color: rgb(128, 0, 128);">QWidget</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(0, 0, 0);">*</span>parent<span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(128, 128, 0);">const</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(128, 0, 128);">QStyleOptionViewItem</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(0, 0, 0);">&</span>option<span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(128, 128, 0);">const</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(128, 0, 128);">QModelIndex</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(0, 0, 0);">&</span>index<span style="color: rgb(0, 0, 0);">)</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(128, 128, 0);">const</span><span style="color: rgb(0, 0, 0);">;//创建编辑器</span>

<span style="color: rgb(0, 0, 0);"><span style="color: rgb(128, 128, 0);">void</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(0, 0, 0); font-style: italic;">setEditorData</span><span style="color: rgb(0, 0, 0);">(</span><span style="color: rgb(128, 0, 128);">QWidget</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(0, 0, 0);">*</span>editor<span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(128, 128, 0);">const</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(128, 0, 128);">QModelIndex</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(0, 0, 0);">&</span>index<span style="color: rgb(0, 0, 0);">)</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(128, 128, 0);">const</span><span style="color: rgb(0, 0, 0);">;//设置编辑器数据</span></span>

<span style="color: rgb(0, 0, 0);"><span style="color: rgb(0, 0, 0);"><span style="color: rgb(128, 128, 0);">void</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(0, 0, 0); font-style: italic;">setModelData</span><span style="color: rgb(0, 0, 0);">(</span><span style="color: rgb(128, 0, 128);">QWidget</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(0, 0, 0);">*</span>editor<span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(128, 0, 128);">QAbstractItemModel</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(0, 0, 0);">*</span>model<span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(128, 128, 0);">const</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(128, 0, 128);">QModelIndex</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(0, 0, 0);">&</span>index<span style="color: rgb(0, 0, 0);">)</span><span style="color: rgb(192, 192, 192);"> </span><span style="color: rgb(128, 128, 0);">const</span><span style="color: rgb(0, 0, 0);">;//设置model数据</span></span></span>

<span style="color: rgb(0, 0, 0);"><span style="color: rgb(0, 0, 0);"><span style="color: rgb(0, 0, 0);">itemDelegate头文件代码</span></span></span>

#ifndef ITEMDELEGATE_H#define ITEMDELEGATE_H#include <QItemDelegate>class itemDelegate : public QItemDelegate{public:    itemDelegate(QObject *parent = 0);    ~itemDelegate();protected:    QWidget* createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const;    void setEditorData(QWidget *editor, const QModelIndex &index) const;    void setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const;};#endif // ITEMDELEGATE_H

itemDelegate.cpp代码

#include "itemdelegate.h"#include <QComboBox>itemDelegate::itemDelegate(QObject *parent ):QItemDelegate(parent){}itemDelegate::~itemDelegate(){}QWidget* itemDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const{    QComboBox *comboBox = new QComboBox(parent);    for (int i = 0; i < 10; i++) {        comboBox->addItem(QString("%1").arg('0' + i));    }    return comboBox;}void itemDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const{    QString text = index.model()->data(index, Qt::EditRole).toString();    QComboBox * comboBox = static_cast<QComboBox*>(editor);    int tindex = comboBox->findText(text);    comboBox->setCurrentIndex(tindex);}void itemDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const{    QComboBox *comboBox = static_cast<QComboBox*>(editor);    QString text = comboBox->currentText();    model->setData(index, text, Qt::EditRole);}

3、将tableview的model设置为CurrencyModel,将第二列代理设置为ItemDelegate

#include "mainwindow.h"#include "ui_mainwindow.h"#include "currencymodel.h"#include "itemdelegate.h"#include <QtDebug>MainWindow::MainWindow(QWidget *parent) :    QMainWindow(parent),    ui(new Ui::MainWindow){    ui->setupUi(this);    QMap<QString, double> currencyMap;    currencyMap.insert("AUD", 1.3259);    currencyMap.insert("CHF", 1.2970);    currencyMap.insert("CZK", 24.510);    currencyMap.insert("DKK", 6.2168);    currencyMap.insert("EUR", 0.8333);    currencyMap.insert("GBP", 0.5661);    currencyMap.insert("HKD", 7.7562);    currencyMap.insert("JPY", 112.92);    currencyMap.insert("NOK", 6.5200);    currencyMap.insert("NZD", 1.4697);    currencyMap.insert("SEK", 7.8180);    currencyMap.insert("SGD", 1.6901);    currencyMap.insert("USD", 1.0000);    itemDelegate *pdelegate = new itemDelegate();    ui->tableView->setItemDelegateForColumn(1, pdelegate);    CurrencyModel *pcurrencyModel = new CurrencyModel();    pcurrencyModel->setCurrencyMap(currencyMap);    ui->tableView->setModel(pcurrencyModel);}MainWindow::~MainWindow(){    delete ui;}void MainWindow::on_pushButton_clicked(){    ui->tableView->model()->insertRows(ui->tableView->model()->rowCount(), 1);    CurrencyModel *model = dynamic_cast<CurrencyModel*>(ui->tableView->model());    model->currencyMap.insert("a", 100);    qDebug() << ui->tableView->model()->rowCount();}void MainWindow::on_pushButton_2_clicked(){    int row = ui->tableView->model()->rowCount();    ui->tableView->model()->removeRows(row, 1);    CurrencyModel *model = dynamic_cast<CurrencyModel*>(ui->tableView->model());    model->currencyMap.erase(model->currencyMap.begin() + row - 1);    qDebug() << ui->tableView->model()->rowCount();}

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